A cokpobation obi wis



C. T. EVANS.

ELECTROMAGNETIC BLOW-GUT DEWCE.

APPLICAI'ION HLED NOV. 23; IBIS.

Patented Aug. 12, 1919,

gNVEN TOR.

A TTORNE V proposed to insure centering of the are by shows certain embodiments 0 UNITED STATES PATENT OFFICE.

CLARENCE '1. EVANS, 0F MIIl'WLUm, WISOON SIN, ASSIGNOR 1'0 m CUTLER- MFG. 00., OF MILWAUKEE, WISCONSIN, A. CORPORATION OF comm.

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' specification of Letter: i'atent.

Patented Aug. 12,1919.

Application filed nmmim :a', me: Serial to. 138,948-

To all whom it may concern:

Be it known that I, Cmnnucn T. Evans,

a citizen of the United States, residing at -Milwaukee, in the county of Milwaukee tric switches are preferably designed to w pcl the are drawn between the switch contacts away from the winding of the blowout device and todirect the arc upwardl be tween the pole pieces of the blowout evice for interruption. However, much difiiculty has been experienced with this type of blow outdevioe due to the tendency thereof to deflect the are against one of the pole pieces,

which quite frequently results in quick destruction of the insulatin chute commonly provided between the po e pieces and the are. It has been rop to insure such deflection o the are by provi mg a tortuous magnetic. circuit for the blowout device relative to thearc but so far as applicant is aware this has not roven a satisfactory solution of the prob em.

According to the present invention it 1! concentration oi the magnetic flux "of the blowout device in a relation. to theme such as to reverse the normal-curvature of the magnetic lines of force which would otherwise deflect the are toward one of the pole pieces, such concentration'being preferably efiected contiguous to the source of the are. This method maybe readily carried out in practice and the accompan g draw ng the invention which have given very satisfactory results.l

In the drawing, Figure '1 is a perspectweymw of a blowout eviee and a pair ,of arcmgrgontects, one side of the blowout device ing broken away to disclose the contacts. 4

- the are drawn Figs. 2 andv 3 are respectivel a front elevational and top Ian view 0 Fi 1;

Fig. 4: is a side e evational view 0 a modified form of blowout device and associated contacts; and,

Fig. {5 is a front elevational view of Fi 4. v fieferring to Figs. 1 to 3, the blowout device comprises an electromagnetic winding 1 having magnetic ole pieces 2 and 3, ins'ulating pole shielcs 4 and 5 and a transverse insulating barrier 6, said shields and barrier formin the usual insulating chute. Contacts 7 an 8 are arr-an d between the pole pieces and within the insulating chute -m the usual relation but are of special construction. Whereas contacts" are ordinarily formed of non-magnetic material, commonly Popper, these contacts, the'bulk of which ria are respectivelyprovided with magnetic inserts 9 and 10. It 18 to be under 'stood, however, that the contacts might be arc travels up the faces of these contactswith 'a tendenc to extend rearwardly of the contact 7 and omrdly from the contact 8.

For .the monient disregarding the metal inserts in the contacts, and mining olarity of the winding-1 such as'would e eel: repulsion of the ar e magnetic lines of force between the po e pieces would tend to bow to subject the arc in' art to repelling lines of force concave wit 1 respect to sai arc and in partto repelling lines'offoree convex withres t to said are. Thus while mween the contacts would always be.v repelled at right angles to the m etic linespf force, that POI'tlOIlth'BlOOf subjectsdto repelling lines of force convex with'respect thereto'would tend to shift toward one or the otherof thexpole pieces.

On the other hand, with the contacts rovided with magnetic inserts as deseri it will be observed that said inserts will conma be of copper, or other desired matecentrate the magnetic flux between the pole pieces adjacent to the source of the arc and will moreover so concentrate the flux that the density of the flux in the region of the arc will be obtained midway between the .-.P9l -pieees. consequence,

the; magnetic lines of force at the source of the will tend to bow as indicated in dotted lines, Figs. 2 and 3, said figures respectively representin the magnetic lines of forcein a vertical 1) ans and a horizontal lane substantially throughthe contacts.

I hat is to'say, the described concentration.

the chute in the manner previously de-.

scribed. It is, of course, to bounderstood that the centering of the arc becomes less in: ortant as the arc becomes'attenuated and it has been found that if the are be held to a centered course during a substantiel degree of travel thereof it will inherently tend to hold to the same course throughout its travel. Accordingly it is not wential to insure .the above described curvature of the magnetic lines of force throughout the entire range of the arc.

Referring nbw to Figs. 4 and 5, the same show contacts'll and 12 of usual construction, that is, of non-magnetic material, and specially constructed pole ieces 18 and 14 to eflect concentration of the magnetic flux adjacent to the source of the are similar to that described. In this instance the pole pieces are respectively cut away contiguous to the contacts on corresponding lines 15 and 1B. As so formed the pole pieces are hook shaped and provide for concentration.

of the magnetic flux along the line of an are or larch over the contacts w th the result that the magnetic lines of forcethroughout the of such arch will tend to curve toward the contact 12, asillustrated in dot-" ted 'lines, Fig. 5, or in other words, substantially as in Figs. 2 and 3 with the same resuit.

What I claim as new and desire to secure by Letters Patent is:

1. The method of-centeringan are between the pole pieces of an electromagnetic blowout device, wherein the magnetic flux traverses a single loop ath with respect to the arc and in a direction to repel thearc from the winding of said device, consisting in concentrating the magnetic flux of the device in a relation to the are to reverse the curvature of the mapinetic lines of force of the device which won d otherwise divert the are from centered relation with the pole pieces.

2. The method of centering an arc netween the .pole pieces of an electromagnetic blowout device, consisting in Boconcentrating the magnetic flux of the device that the 'ing and density thereof in-the region of the arc is fireatest midway between the pole pieces of t e device.

3. The method offcentering an arc, b6-r tween the pole pieces of an electromagnetic device consisting in concentrating the magnetic flux of the device adjacent to the source of the are and in such a manner that the density of the magnetic flux in the region of the arc is greatest midway between the pole ieces .of the device.

e method of centering an are between the pole pieces-of an electromagnetic blowout device, wherein the magnetic flux tends to'repel the are from the winding of 5. The combination with contacts adapted to draw an arc therebetwecn, of an electromagnetic blowout device including a wind ing and. pole pieces for said winding disposed on opposite sidesof said contacts, said winding mg a magnetic flux to repel therefrom the are drawn between said contacts andcertain of said elements being'constructed to concentrate the magnetic'flux of said device in a relation to the are to reverse oi the magnetic lines of force of said device which would otherwise efleot shifting of the arc laterally and to thereby insure centering of the are between said pole pieces.

6.111s cpmouiation with contacts adapted to "draw an arc therebetween, of an electromagnetic blowout device-including a wind- V e for said winding dis posed on oppos te s des of and contacts, said winding a magnetic flux to repel therefrom the are drawn between said contact: and certain of said elements being constrl'icted to concentrate the magnetic flux of aid device contiguous to the source of the arc to thereby insure normal curvature of the magnetic lines of force of said device contiguous to the source of the arc substantially parallel to the repelling magnetic lines of force of the are 7. The combination with contacts adapted to drawan arc therebetween, one of said contacts including a magnetic part, of an electromagnetic b owout device including an electronic etic winding and pole pieces for said win mg disposed on opposite sides of said contacts, said contact including said ma etic part providing for concentration of t e magnetic flunbetween said pole pieces and thereby -lgo efl'ect curvature of ing of the are between the pole pieces.

. 8. The combination with contacts adapted to draw an arc therebetween, each having a magnetic part, of an electromagnetic blowout device including a winding and pole pieces therefor disposed on opposite sides of said contacts the magnetic parts of said contacts providing for concentration of the magnetic flux between the pole pieces and thereby tending to effect-curvature of magnetic lines of force of said device acting to repel the are such as to insure centering o the are betweenthe pole pieces.

9. The combination with contacts adapted to draw an arc therebetween, of an electromagnetic blowout device'including a winding and pole ieces. for said winding disposed on opposite si es of said contacts, said winding creating a magnetic flux to repel therefrom the are drawn between said contacts and certain of said elements roviding for concentration of the magnetic ux of the device so that the density thereof in the region of the arc is greatest midway between said pole pieces.

10. The combination with contacts adapted to draw an arc'therebctween, of an electromagnetic blowout device including a winding and pole pieces for said winding disposed. on opposite sides of said contacts, said winding creating a magnetic flux to repel therefrom the are drawn between said contacts and certain of said elements providing for concentration of the magnetic flux of said device adjacent to the source of the arc in such a manner that the density of the magnetic flux in the region of the arc is greatest midway between said pole pieces.

In witness whereof I have hereunto subscribed my name.

' CLARENCE T. EVANS. 

